An all-inclusive fluid flow device that can variably magnify differential pressure, measure, and control a flow of a fluid is described. Various procedures, including measuring, controlling, balancing, or calibration procedures can leverage a variably magnified differential pressure measurement. Differential pressure measurements can be measured across the fluid flow device such that a first pressure measurement is taken upstream of the fluid flow device while a second pressure measurement is taken downstream of the fluid flow device. Moreover, one or more of the various pressure measurements, and in particular the downstream pressure measurement, can be performed at stagnation zone where the flow has stagnated. Such can provide significant magnification and/or turndown capabilities and the magnification can vary based on a damper position and/or apertures dimensions.

A method/structure for calibrating a product fluid flow device having one or more apertures with aggregate area A.sub.o, where fluid flows along a fluid flow path therethrough in response to pressure differentials ΔP across the apertures. Calibration is effected relative to a calibration fluid flow device having a geometry and operational parameters corresponding to those of the product fluid flow device. A piecewise curved calibration controller establishes calibration conditions and generates a discrete point calibration flow rate (dpCFR) Function by measuring at a sparse set of points in a range of interest and determining a piecewise curved mathematical representation of fluid flow through the calibration fluid flow device. Data representative of the CFR function is transferred to a product blade controller, which processes the mathematical representation, and controls fluid flow through product fluid flow device based on values extracted from the received dpCFR Function.

A UV sterilization system is provided. In some embodiments, the UV sterilization system includes a first UV LED device having a LED circuit and LED emitters. The UV sterilization system can include a sensor electrically coupled to the first UV LED device, the sensor configured to interrupt the operation of the first UV LED device upon detecting movement within an air conditioning system. The UV sterilization system can include a power module electrically coupled to the sensor, where the power module is electrically coupled to a power supply of the air conditioning system. In some embodiments, the air conditioning system can include a packaged terminal air conditioner (PTAC) unit or a split-air air-conditioner system, and the UV sterilization system can be a part of the PTAC unit or split-air air-conditioning system. In some embodiments, the sensor includes a motion sensor and/or an occupancy sensor.

The present disclosure relates to a heating, ventilation, and/or air conditioning (HVAC) system having a heat exchanger configured to thermally regulate a supply air flow, where the heat exchanger includes a thermoelectric device, a first plurality of fins coupled to the thermoelectric device, and a second plurality of fins coupled to the thermoelectric device. The first plurality of fins extend into a supply air flow path of the supply air flow to transfer thermal energy between the thermoelectric device and the supply air flow and the second plurality of fins convectively transfer thermal energy between the thermoelectric device and a working fluid exterior the supply air flow path.

A fluid flow device that can measure and control a flow of a fluid is described. Various procedures, including measuring, controlling, balancing, or calibration procedures can leverage differential pressure measurement. These differential pressure measurements can be measured across the fluid flow device such that a first pressure measurement is taken upstream of the fluid flow device while a second pressure measurement is taken downstream of the fluid flow device. Moreover, one or more of the various pressure measurements, and in particular the downstream pressure measurement, can be performed at stagnation zone where the flow has stagnated. Such can provide significant amplification and/or turndown capabilities.

A method for indicating to a user the expected time for an air purifier to achieve a target level of pollution in a room by: (A) acquiring the current level of pollution (CP) in said room; (B) acquiring current air flow speed (CAFS) through said air purifier; (C) comparing the current level of pollution (CP) with a pre-determined target level of pollution (IP); (D) calculating the expected time (T) required to reduce current pollution (CP) to said target level of pollution (IP) at current air flow speed (CAFS); (E) indicating said expected time (T) required to reduce current pollution to said target level of pollution at current air flow speed to a user; and (F) repeating steps (A) to (E).

A variable air flow air conditioning (HVAC) systems and methods are disclosed. In example embodiments, one or more variable speed fans or air-moving devices are in communication with ducts connecting one or more zones of a structure or other space to be air conditioned. Zone temperature sensors and air flow measurement are provided to obtain particular measurements relative to the zone it is serving while communicating with a central control. Optionally, a distributed control system can be provided such that zone sensors communicate with both the central control and its respective zone controller. The control system collects and processes multiple datasets to dynamically and proportionally adjust the volumetric air flows of each of the zones to satisfy any loads or heating/cooling demands while also maintaining a net volumetric air flow across a coil of the indoor heat transfer unit within a preset range. In some example embodiments, enhanced variable air flow air conditioning (HVAC) systems and methods are disclosed.

In one embodiment, a ventilation control system includes a processor; a memory; a calculation module to calculate an inverse protection factor for a structure using a lumped element model, the inverse protection factor being an inverse of a protection factor which is a ratio of contaminant which the one or more infected individuals exhale in the structure and contaminant which the uninfected individual inhales in the structure; and a ventilation control module to control a ventilation system to modify air flowing in the structure. The inverse protection factor is calculated based on operating parameters of the ventilation system, arrangement of spaces of the structure, and locations and relative positions of the infected and uninfected individuals in the structure with respect to air flowing in the structure and influenced by the ventilation system. The ventilation control module is configured to control the ventilation system based on the calculated inverse protection factor.

A droplet range control system includes a first obtainer that obtains environment information indicating at least wind speed in a space, wind direction in the space, temperature in the space, humidity in the space, or spatial scale, a second obtainer that obtains target information indicating positions and directions of faces of a first target and a second target in the space, an estimator that estimates a range of droplets from the first target on a basis of the environment information and the target information, and a controller that, if a respiration area of the second target exists within the range, conditions an environment in the space such that the respiration area gets out of the range.

A fan, in particular axial fan and preferably backward-curved radial fan, having an impeller equipped with blades, an electric motor for rotating the impeller and a device for determining the airflow when the impeller is rotating. The device for determining the airflow includes a volume flow measuring wheel arranged in the air flow, which is arranged upstream of the impeller on the inflow side. The air volume flow is calculated or derived from the rotational speed of the volume flow measuring wheel.